Less dense then water its self
GAO report said hundreds of planes flying commercially today could be vulnerable to having their on board computers hacked.
Yes aids had done more harm than good. The reason why because people in Africa didn't have aids and when aids started to spread around the whole world the Africa gotten so sick they started to die.
Trees serve as a natural force to prevent erosion and hold soil together during rainfall and other periods of weather that might impact the integrity of the soil. However, trees were cut down to build a new shopping center there could be an increased flow of water to a river and also lead to great soil erosion nearby thus increasing the amount of sediment being deposited into the river. Also this new shopping mall could increase the pollutants in a river as well.